Lead and growth status of schoolchildren living in the copper basin of south-western Poland: Differential effects on bone growth

Objective: The study analyzed the relationship between blood lead (BPb) levels and growth status of upper and lower body segments among schoolchildren living in the copper basin of south-western Poland. Materials and methods: Schoolchildren 7-15 years of age (463 males, 436 females) living in the vicinity of copper smelters and refineries were tested for blood lead. Weight, height, symphyseal height (leg, lower segment length), and arm length were measured. Trunk (upper segment including head and neck) length was estimated as height minus symphyseal height. The BMI was calculated using weight/height(2) (kgm(-2)). Results: Mean blood lead in the total sample was 7.7 +/- 3.5 mu gdL(-1) (2.0-33.9 mu gdL(-1)). Blood lead level was significantly and linearly related to reduced weight, height, trunk, leg, and arm lengths. The estimated reduction in height was 5mm per 1 mu gdL(-1) increase in blood lead (5.0 cm per 10 mu gdL(-1)). The reduction occurred in leg length (males, 64%; females 72%) compared to trunk length (males, 36%; females, 28%). Estimated reductions in arm length were 2.0 cm (males) and 2.5 cm (females) per 10 mu gdL(-1) increase in blood lead. Hence, limb (leg and arm) lengths were markedly reduced. Conclusions: Linear skeletal growth was reduced with increased blood lead, even at levels below that considered for action by US CDC standards. The reduction in height occurred primarily in leg length. Arm length was also reduced, suggesting limb lengths in general were affected by blood lead. Results are consistent with lead-associated interruption of (1) major epiphyseal growth plate chondrocyte hyperplasia, hypertrophy, and interrupted matrix calcification as a primary cause of stunted long bone growth, and reduced stature; and (2) attenuated osteoblast activity (proliferation and migration) as a secondary cause of stunted growth in the study population.